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Rasser M.W.,Staatliches Museum fur Naturkunde Stuttgart
Hydrobiologia | Year: 2014

The Miocene Steinheim Basin in SW Germany is an ancient (long-lived) palaeo-lake that has existed over some hundreds of thousands of years. It is an iconic fossil site, because the historically oldest phylogenetic tree of extinct organisms was based on specimens described from this locality. Today the basin contains 30–40 m thickness of lake sediments with planorbid snails of the genus Gyraulus occurring in rock-forming quantities. The shells are morphologically highly disparate with forms ranging from the tiny, planispiral founder species Gyraulus kleini, to fragile corkscrew-like uncoiled forms and to large trochiform morphs with thick shells. In total, this presumably monophyletic species flock contains 17 species distributed in time and space, all of which are endemic, except for the founder species. Up to nine of them occur in a single sedimentary level and are inferred to have lived together. Such an extreme rate of endemism makes fossil Lake Steinheim special among extant and fossil lakes. This review article summarises and discusses the species concept(s), indications for endemism, speciation processes, the phylogenetic concept(s) and factors controlling evolution. It also provides directions for future research. © 2013, Springer Science+Business Media Dordrecht.


Richling I.,Staatliches Museum fur Naturkunde Stuttgart | Bouchet P.,French Natural History Museum
Biodiversity and Conservation | Year: 2013

Recent literature abounds with reports of the decline and extinction of the endemic species of Achatinellidae and Partulidae in the Hawaiian and Society Islands, respectively, resulting from the introduction of the predatory snail Euglandina rosea. Here, we describe a previously unrecognised radiation of helicinid land snails from the Gambier Islands of French Polynesia, with up to seven species co-occurring in a single locality and up to eight species on a single island. This radiation had already become extinct (nine of ten species) several decades before the expansion of E. rosea in the Pacific, and even before the species were collected for scientific study. The Gambier Islands case study shows that massive extinctions of endemic land snails had already taken place in the nineteenth century, but have remained largely unrecognised and undocumented. Nine of the ten species are new to science and are described here almost entirely based on empty shells collected from the shell bank of the soil after the extinction had already taken place. This helicinid radiation alone increases the number of documented global mollusc extinctions by almost 2 %. Most of the species are minute and, at 1.5 mm, rank among the smallest, if not the smallest, species in the family. Several have apertural barriers and one has opercular apophyses-character states not previously documented in Pacific helicinids. Whereas the only surviving Gambier species belongs anatomically to the genus Sturanya, representative helicinid species from the Austral, Society and Cook Islands are not congeneric with it, and the generic name Nesiocina is here established for the latter taxa. It is hypothesised that the extinct Gambier species were also Nesiocina. © 2013 Springer Science+Business Media Dordrecht.


Rasser M.W.,Staatliches Museum fur Naturkunde Stuttgart
Zoosystematics and Evolution | Year: 2013

Among others, "Darwin's dilemma" is referred to as Charles Darwin's perception that his theory on the origin of species suffers from a scarcity of fossil evidence such as transitional forms between taxa. In 1867, only afew years after the publication of Darwin's "Origin of Species", Franz Hilgendorf published a phylogenetic tree of Miocene planorbid snails from the Steinheim meteorite crater lake in SW Germany. This tree was widely ignoredby Darwin, although it would have been a perfect solution for his "dilemma". Surprisingly, the reason for his ignorance was the influence of contemporary German and US palaeontologists, who had been followers of the "anti-Darwinian" orthogenesis concept, which implies the consistency of species and the refusal of the idea that one species may branch into two new species. During the last decades, several studies have supported the appropriateness of Hilgendorf's concept, whom S. J. Gould called one of the first "Darwinians". With good reason his tree of planorbid snails is seen today as the first phylogenetic tree of fossils and one of the first fossil evidences for Darwin's descendent-theory. ©2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Schoch R.R.,Staatliches Museum fur Naturkunde Stuttgart
Journal of Systematic Palaeontology | Year: 2013

Phylogenetic analysis of a large dataset (72 taxa, 212 characters) focuses on the in-group relationships of temnospondyls, the largest lower tetrapod clade. Representatives of all clades and grades were considered, spanning the entire stratigraphical range of temnospondyls from the Early Carboniferous through to the Early Cretaceous. Several major groups are defined phylogenetically (node or branch-based) rather than by apomorphies. The following groups were unequivocally found to be monophyletic: Edopoidea (node), Dvinosauria (stem, excl. Brachyopidae), Dissorophoidea (node), Eryopidae (stem), and Stereospondyli (node). The latter encompass three well-defined, branch-based taxa: Rhinesuchidae, Trematosauria and Capitosauria. Trematosauria (stem) contain Trematosauroidea (node), which includes the classic trematosaurids, metoposaurids, and possibly part of the rhytidosteids (Peltostega) but their in-group relationships remain unsettled; most other short-snouted stereospondyls (chigutisaurids, brachyopids, Laidleria and the plagiosaurids) are probably monophyletic and likely nest in some form with trematosauroids. Capitosauria (stem) include the Capitosauroidea (node) spanned by Parotosuchus and Mastodonsaurus, with the successive stem taxa Edingerella, Benthosuchus, Wetlugasaurus and Watsonisuchus. In all variant analyses, edopoids form the basalmost temnospondyl clade, followed by a potential clade (or grade) of small terrestrial taxa containing Balanerpeton and Dendrerpeton (Dendrerpetontidae). All taxa higher than Edopoidea are suggested to form the monophyletic stem taxon Eutemnospondyli, tax. nov. The remainder of Temnospondyli fall into four robust and undisputed clades: (1) Dvinosauria; (2) Zatracheidae plus Dissorophoidea; (3) Eryopidae; and (4) Stereospondyli. These taxa are together referred to as Rhachitomi (node). Eryopidae and Stereospondylomorpha are probably monophyletic, here referred to as Eryopiformes (tax. nov.). The position of Dissorophoidea + Zatracheidae is still ambiguous; it may either form the sister taxon of Dvinosauria, or nest between Dvinosauria and Eryopiformes, whereas there is no support for Euskelia (Dissorophoidea + Eryopidae) after basal taxa of each clade are better understood. © 2013 Copyright Taylor and Francis Group, LLC.


Schweigert G.,Staatliches Museum fur Naturkunde Stuttgart
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen | Year: 2011

The Solnhofen Limestones represent one of the most important sources for crustacean diversity in the Jurassic and even for their fossil record in the Mesozoic. A brief overview of the history of science since the beginning of 18th century and the circumstances of the fossil recoveries are provided. The fossils come from various localities of slightly different ages (late Kimmeridgian - early Tithonian). Most specimens did not live at their later places of burial, but were swept in as exuviae from more or less distant neighboring environments. These reasons are responsible for the great diversity of genera and species described so far. Three species of caridean shrimps from the Solnhofen Limestones of Eichstätt and Zandt are newly introduced: Hefriga rogerfrattigianii, Hefriga norbertwinkleri, and Harthofia polzi. © 2011 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.


Schoch R.R.,Staatliches Museum fur Naturkunde Stuttgart | Witzmann F.,Humboldt University of Berlin
Lethaia | Year: 2012

The plagiosaurid Gerrothorax pulcherrimus from the Triassic of Greenland and Germany is represented by skulls ranging from 4 to 12cm in length and sheds light on ontogeny, individual variation, and variation in time and space. Ontogeny was remarkably stable in G.pulcherrimus, with the smallest known specimens resembling the adults closely in most features. A true ontogenetic change is evident in the ornament of dermal bones, in that the smallest specimens have ridges whereas in the successively larger ones, pustules spread over increasingly larger areas. The skull becomes proportionally longer, and the adductor chambers relatively narrower. The positive allometry of both the orbits and the interpterygoid vacuities suggests that the eye supporting musculature - rather than the jaw adductors - increased proportionally during growth. Individual, not age-related variation in the dermal skull roof affects partial fusion of parietals, presence and extent of the interfrontoparietal, and the morphological pattern of the posterior skull table. The ventral surface of the basal plate of the parasphenoid ranges from smooth over poorly to heavily ornamented or dentigerous. Considering the impressive longevity of more than 35Myr, the morphological changes of G.pulcherrimus are minor. Our ecological interpretation for G.pulcherrimus is that it relied on the permanent presence of water, but was flexible with respect to the size and nature of the water body as well as to changes in salinity. The unparalleled extent of evolutionary stasis may therefore be based on the ecological flexibility of this morphologically so tightly constrained temnospondyl. □Ecological flexibility, ontogeny,Temnospondyli, Triassic, variation. © 2011 The Authors, Lethaia © 2011 The Lethaia Foundation.


Ziegler R.,Staatliches Museum fur Naturkunde Stuttgart
Geobios | Year: 2012

The moles from twelve early Oligocene fissure fillings from Liptingen, Herrlingen and Ehrenstein on the Swabian Alb, and from Haag and Möhren on the Franconian Alb are described. The samples correlate with the early Oligocene standard levels of Soumailles (Paleogene mammal unit MP 21) and Villebramar (MP 22). They include the earliest record of the genus Geotrypus and the new species Geotrypus minor. The slender humerus with its short teres tubercle and shallow brachialis fossa suggests that its burrowing abilities were less developed than in later species of the genus. Myxomygale vauclusensis from Möhren 13 is the largest known sample of the species. The smaller Myxomygale species is closely related to the early Miocene M. minor. With four to five species the samples from Ehrenstein 12 and Möhren 13 are the most diverse talpid associations described to date in the early Oligocene. © 2012 Elsevier Masson SAS.


Schoch R.R.,Staatliches Museum fur Naturkunde Stuttgart
Fossil Record | Year: 2012

The phylogeny of the largely Permian temnospondyl group Dissorophidae` is analyzed for the first time. Although hampered by poor preservation and incompleteness of finds, new data add substantially to our knowledge of the group. An analysis of 25 taxa and 70 characters gave the following results. (1) The Dissorophidae and Trematopidae each form monophyletic groups that are more closely related to one another than either of them is to amphibamids. Olsoniformes and Amphibamidae are each defined by clear-cut autapomorphies, making it unlikely that amphibamids are dwarfed dissorophids or olsoniforms. (2) Ecolsonia nests with Fedexia at the base of the Trematopidae. (3) The Dissorophidae falls into two major clades, the Dissorophinae sensu stricto (Dissorophus, Broiliellus) and the Cacopinae (Cacops, Kamacops, Zygosaurus). The Cacopinae is much better supported than the Dissorophinae. Platyhystrix and Aspidosaurus form successive sister taxa of all other dissorophids. Incompletely known dissorophids were found to nest as follows: (a) Brevidorsum, the Admiral Taxon and Rio Arriba Taxon at the base of the Cacopinae and (b) Conjunctio multidens forms an unresolved trichotomy with dissorophines and cacopines. The significance of osteoderms in dissorophid phylogeny is found to be much smaller than hitherto considered. ©2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Schoch R.R.,Staatliches Museum fur Naturkunde Stuttgart
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen | Year: 2011

A new find of a tetrapod mandible with unique teeth is reported from the Middle Triassic Lower Keuper. The outline of the dentary, morphology of the teeth and their emplacement suggest that the remain represents a new procolophonid parareptile. The abbreviated dentary, the high coronoid process, and the shape of the teeth resemble those of leptopleuronines. Unique features are the crown morphology, marked parallel striations, the possession of two similar, very large durophagous teeth, the edentulous anterior portion, and the lack of a coronoid suture. Thus, although the jaw resembles procolophonids in some features, it is argued that referral to this group needs recognition of more clearly established character-states, prompting the search for more complete material in the same deposits. © 2011 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.


Lehnert M.,Staatliches Museum fur Naturkunde Stuttgart
Phytotaxa | Year: 2012

A summary of the species of Cyathea sensu strictu with pinnate to pinnate-pinnatifid fronds is presented. All species are strictly Neotropical and are found throughout the entire range of the genus in the Western Hemisphere, but most species occur in the mountainous regions of northern South America and Central America. This artificially delimited group includes the species formerly recognized as the segregate genus Cnemidaria, which form a monophyletic group within Cyathea together with some species previously not recognized as Cnemidaria. This group is characterized by a general lack of hairs, cartilaginous laminar texture, petiole scales that have white margins or that are completely white, and large sori with diameter ≥ 1 mm and 30-40 sporangia per sorus. Cnemidaria-type spores with at least three large equatorial pores dominate in this group but are neither omnipresent nor exclusive to it. The remainder of the pinnate to pinnatepinnatifid species of Cyathea includes predominantly exindusiate species that have moderately to densely pilose laminae and relatively small sori with diameter ≤ 1 mm and ± 20 sporangia per sorus. Twelve new combinations are made and the following three new names are proposed: Cyathea cnemidaria (= Cnemidaria tryoniana), C. glandulifera (= Cn. glandulosa), C. suprapilosa (= Cn. suprastrigosa). A key to all species of Cyathea with pinnate to pinnate-pinnatifid fronds is provided. Hybrids are not treated. © 2012 Magnolia Press.

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